The present invention relates to a hot blast stove installation for heating cold blast to form hot blast and of the type including a plurality of hot blast stoves each alternately operable during a heating phase and a blowing phase and a cold blast main for supplying cold blast to respective of the stoves during the blowing phases thereof. The present invention particularly is directed to such a hot blast stove installation of the type wherein the temperature of the cold blast in the cold blast main is relatively high compared to ambient temperature, for example between 100.degree. C. and 300.degree. C.
Such a hot blast stove installation is disclosed in DE-PS No. 3,126,494, wherein cold blast at such relatively high temperature is fed alternately to the plurality of hot blast stoves during the blowing periods or phases of operation thereof. During heating periods or phases of operation of the respective stoves combustion occurs in the stoves by the supply thereto of combustion air and fuel gas. The waste gas temperature resulting from such combustion can only be so high due to limitations of the structure, particularly the brick work structure of the stoves. This imparts an inherent limitation to the extent of combustion that can be achieved during the heating phase. When the temperature of the cold blast supplied to the stoves during the respective blowing periods is relatively high, this will lead to a relatively high mean and maximum waste gas or exhaust gas temperature during the heating periods or phases of operation. This results in an inherent limitation in the output of the hot blast stove installation.
In DE-PS No. 3,126,494, a heat exchanger circuit is connected on a primary side thereof to the exhaust gas or flue gas collecting main of the hot blast stove installation. As a result, although the waste heat of the waste or flue gas is used for preheating the combustion air and/or the fuel gas, there still results the above discussed disadvantage resulting from the relatively high temperature of the cold blast. Particularly, there results the above discussed limitation on the overall power of heat output of the stoves and the installation.